1. Field of the Invention
This invention relates to specialized vehicles and more particularly to a special vehicle for dispensing molten asphalt into containers. 2. Description of the Prior Art
As is well known in the art molten asphalt is employed for various jobs in the construction arts such as for seal coating roadways, runways and the like, and also for comparatively small jobs such as the filling of cracks and expansion joints in paved surfaces, and various spot applications such as on paved surfaces, roofs, and the like.
In the relatively large jobs, such as the above mentioned seal coating of paved surfaces, where large quantities of molten asphalt are to be used, the molten asphalt is placed in special transport trucks at the asphalt plant and delivered directly to the job site where it is transferred either to interim storage tanks or directly to heated spray applicator trucks. In some instances, the molten asphalt is mixed at the job site with special additives such as shredded rubber, prior to being applied to the paved surface. At any rate, such a procedure must be accomplished rather rapidly to prevent excessive cooling of the molten asphalt, to keep the needed interim storage facilities to a minimum, and to keep the equipment and labor costs to a minimum. Even when this procedure is most efficiently accomplished, it is an expensive matter and as such cannot be economically justified on the comparatively smaller jobs due to the smaller quantities of material needed, the slow and often interrupted application schedules and the like.
Therefore, it is a common practice to place molten asphalt, or molten asphalt compositions, in manually handleable containers at a manufacturing facility and ship the desired quantity to a job site on an as needed and when needed basis. When the asphalt is needed at a job site, the containers are torn open and the asphalt, which has since cooled and thus, solidified, is placed in a heating vessel which is usually a tank that is an integral part of the mechanism which is to be used to apply the asphalt. When the desired temperature of the molten asphalt is reached, normally a minimum of about 275.degree. F., it is applied in accordance with procedures suitable for the particular job.
The commonly used prior art method for placing the asphalt into manually handleable containers is in the form of an elongated conveyor system. At a first station of the prior art conveyor system, a plastic package or liner is inserted into an open corrugated cardboard box and transported by the conveyor to a second station below the outlet of a stationary molten asphalt dispensing unit. At this second station, the dispensing mechanism deposits a predetermined amount of the molten asphalt, usually about sixty pounds, in each container which is passed thereunder. After such filling, the containers are transported to a third station on the conveyor system where the asphalt filled packages and their containers are closed, and from there they are transported to the last station where they are manually off-loaded from the conveyor system and placed on pallets for subsequent shipping.
The prior art method described above has several drawbacks. In the first place, the off-loading and stacking tasks must be accomplished without excessive delays so as not to halt production. Therefore, the asphalt in the containers is still in the molten state when the off-loading and pallet stacking operations need to be accomplished. The molten state of the asphalt rules out the use of all but the most sophisticated mechanized equipment, and the costs of such equipment cannot be justified in operations of this sort. Therefore, the asphalt containers are manually off-loaded and stacked on the pallet, and this is a very arduous and uncomfortable job due to the weight of the asphalt containers and the heat radiating therefrom.
The second, and most serious, problem with the prior art conveyor system for containerizing asphalt involves the lack of portability of the equipment. High shipping costs dictate that a prior art conveyor system cannot be economically used to containerize asphalt for use outside of a given area. Thus, a prior art conveyor system is intermittently used in that it is normally capable of satisfying the needs of its immediate area with, for example, two days of operation per week. Providing containerized asphalt for areas outside of the immediate vicinity of an existing prior art conveyor system involves either paying the high shipping costs, or building and manning other conveyor systems which will also be intermittently operated.
The above described drawbacks and shortcomings of the commonly used prior art asphalt containerization system have been overcome to a great extent by a new method which is fully disclosed in a pending U.S. Patent Application entitled: METHOD FOR CONTAINERIZING ASPHALT, Ser. No. 144,301, filed on Apr. 28, 1980 by J. Ronald Robinson, with the application having the same assignee as the present invention.
Briefly, this new method comprises the placement of a first tier of open top containers in side-by-side relationship on each of a plurality of pallets which are arranged in a linearly aligned juxtaposed relationship. Then an asphalt dispenser vehicle is slowly moved in a path which is parallel to the aligned pallets so that an asphalt dispenser hose provided on the vehicle may be moved from container to container for filling purposes. When each container has been filled in this manner and subsequently closed, a second tier of containers is placed on each pallet, and the dispenser vehicle is again moved in the parallel path for filling of the containers of the second tier. When the second tier of containers are filled and closed, the steps of this method are again repeated for a third tier, and if desired, for additional tiers.
In developing and testing the above described method for containerizing asphalt, it was found that the conventional well known asphalt handling vehicles, such as highway transport trucks, spray applicator trucks and the like, could be used provided they had some simple modifications made thereto. However, some of the inherent characteristics of such vehicles are beyond reasonable modification and those characteristics make their use in this application a very slow, awkward and costly operation.
The above described vehicles are very awkward to use due to the fact that the vehicle's operator is located in a cab at the front of the vehicle and the asphalt is being dispensed from a hose at the back of the vehicle. It is very difficult, if not impossible, for the vehicle's operator to see what is going on; he can't tell when it is time for him to move and he can't tell how far he should move. In many vehicles of this type, the controls for the asphalt pump, and other such equipment, are located in the driver's compartment, and thus the operator who can't see what is going on is the one who must control the flow of the asphalt. Further, such vehicles are equipped with two engines, one to move the vehicle and another to run asphalt mixing augers, dispensing pumps, and the other special components provided on this type of vehicle. When used for their intended purposes, such two engine configurations are highly justifiable. However, in this highly specialized application, it is very costly to operate one engine to handle the asphalt dispensing operations and operate a second engine which moves the vehicle a few feet and then idles until several containers are filled, and then moves the vehicle a few more feet.
Therefore, a need exists for a new and useful asphalt dispenser vehicle which is especially designed for use in containerizing molten asphalt.